JPH0219392B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an air conditioner equipped with a refrigerant flow rate control device that appropriately controls the amount of refrigerant circulated in a refrigeration cycle.

[Prior art]

Normally, in a refrigeration cycle, the appropriate flow rate of refrigerant varies depending on the evaporation temperature, and as the evaporation temperature increases, a larger flow rate of refrigerant is required. If the adjustment range of the refrigerant flow rate is small and the evaporation temperature is high, the refrigerant flow rate will be insufficient, and the degree of superheating of the refrigerant at the evaporator outlet will become too large, causing the compressor temperature to rise, or if the evaporation temperature is low, the refrigerant flow rate will be insufficient. The flow rate may become excessive, causing liquid backflow in the compressor. Therefore, in order to solve these problems, a refrigeration cycle as shown in FIG. 1 can be considered. That is, in Figure 1, 100
is a compressor, 101 is a four-way switching valve, 102 is a non-use side heat exchanger that exchanges heat with outside air, 103 is a use side heat exchanger that exchanges heat with water, 104 is a non-use side and use side heat exchanger 102, A main throttle device 3 is provided between the tubes 103 and 3 is a pressure reducing device, and as shown in FIG. .
The main constriction section 32, the outer tube 31, and the main constriction section 3
The inlet pipes 35, 36 and the outlet pipe 37 are provided so that the refrigerant flow passage 33 between the two is parallel to each other,
The inlet pipes 35 and 36 are connected to the outlet of the dryer 110, the outlet pipe 37 is connected to the inlets of third and fourth check valves to be described later, and the inlet pipe 36 is provided with an electric expansion valve 38. This is what I did. 1
05 and 106 are first and second check valves that allow flow only from the non-use side heat exchangers 102 and 103 to the dryer 110, respectively; 107 and 1
08 are third and fourth check valves that allow flow from the outlet pipe 37 of the main throttling device 104 only to the utilization side and non-utilization side heat exchangers 103, 102.

Next, the effect will be explained. First, the flow direction of the refrigerant during cooling operation is shown by solid arrows. Compressor 10
The high-temperature, high-pressure refrigerant gas discharged from 0 passes through the four-way valve 101, is condensed and liquefied in the non-use side heat exchanger 102, and then passes through the first check valve 105 and the dryer 110.
and reaches the main aperture device 104. In the pressure reducing device 3, the liquid refrigerant supplied from the non-use side heat exchanger 102 passes through the dryer 110 and enters the inlet pipe 3.
5 through the main constriction section 32, the pressure is reduced, and the third
It passes through the check valve 107 and evaporates in the user-side heat exchanger 103 to perform a cooling effect. In addition, a part of the liquid refrigerant supplied from the non-use side heat exchanger 102 passes through the dryer 110 and is depressurized by the electric expansion valve 38, evaporates in the refrigerant flow path 33, and circulates in the main constriction section 32. Since the refrigerant is cooled, the flow rate of the refrigerant in the main constriction section 32 increases. That is, as the amount of cooling increases, the gas content in the two-phase flow of refrigerant generated within the main constriction section 32 decreases, and the fluid resistance decreases. Therefore, the electric expansion valve 38
Since the amount of cooling can be changed by adjusting the opening degree of When the electric expansion valve 38 is controlled as shown in FIG.
At the 03 outlet, the refrigerant is completely gasified and slightly superheated, allowing a proper flow rate of refrigerant to be constantly circulated within the refrigeration cycle. By the way, as shown in FIG. 3, the optimum refrigerant circulation amount changes depending on the refrigeration load. In FIG. 3, curve AB shows the optimum refrigerant circulation amount for the refrigeration load. curve
The range packed by ABB' is electric expansion valve 3
The circulation amount ensured by 8 and the range packed by AB'B''A' indicate the circulation amount ensured by the main throttle section 32. However, in the above-mentioned refrigeration cycle, the main throttle section 32 Since the liquid refrigerant from the non-use side heat exchanger 103 is always flowing through, even if the electric expansion valve 38 is fully closed,
The refrigerant circulation amount indicated by AA' is in circulation. Therefore, the amount of refrigerant circulation is controlled to the optimum amount in the range from point A to point B in FIG. There is.

On the other hand, in the range from point B to point D, where the refrigeration load is large, the control range of the electric expansion valve 38 is exceeded, so there is a problem that the optimum refrigerant circulation amount cannot be controlled.

Next, the direction of refrigerant flow during heating operation is shown by the dashed arrow in FIG. The high-temperature, high-pressure refrigerant gas discharged from the compressor 100 passes through the four-way valve 101, is condensed and liquefied in the user-side heat exchanger 103, and then passes through the second check valve 1.
06, passes through the dryer 110 and enters the main squeezing device 104
The action of the main throttling device 104 leading to this is as described above, and the depressurized refrigerant passes through the fourth check valve 108, evaporates in the non-use side heat exchanger 102, and passes through the four-way valve 1.
01 and returns to the compressor 100. During heating operation as well as during cooling operation, there is a range in which the optimal refrigerant circulation amount cannot be controlled.

[Summary of the invention]

This invention was made in view of the above circumstances,
The objective is to always obtain the optimum refrigerant circulation amount even in an air conditioner where the refrigeration load of the refrigeration cycle fluctuates widely.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 4 and 5. In Fig. 4, 100 is a compressor, 101 is a four-way valve, 102 is a non-use heat exchanger that exchanges heat with outside air, and 103 is a use-side heat exchanger 104 that exchanges heat with water. This is a main throttling device provided between exchangers 102 and 103, and is composed of a pressure reducing device 3 shown in FIG. 2 and a solenoid valve 39 provided in an inlet pipe 35 of this pressure reducing device. The electric expansion valve 38 is controlled by a controller (not shown) that detects and calculates the outside air temperature and the outlet water temperature of the user-side heat exchanger 103, and determines the applied voltage based on a signal output according to the calculated values. be done. That is, the valve opening degree is determined by the voltage applied to the electric expansion valve 38. Further, the solenoid valve 39 is closed when the water temperature on the outlet side of the user-side heat exchanger 103 is below a predetermined value during cooling, and the outside temperature is below a predetermined value during heating, and is opened when the temperature is above a predetermined value.
105 and 106 are first and second check valves that allow flow only from the non-use side heat exchangers 102 and 103 to the dryer 110, respectively;
7, 108 are third and fourth check valves that allow flow only from the outlet pipe 37 of the main throttling device 104 to the utilization side and non-utilization side heat exchangers 103, 102; 109;
is connected to the outlet of the dryer 110 and the inlet of the user-side heat exchanger 103 during cooling, and is connected to the main throttle device 10.
4 is an auxiliary cooling capillary tube connected in parallel. Reference numeral 111 denotes an auxiliary capillary reach tube for heating that is connected to the outlet of the dryer 110 and the inlet of the non-use side heat exchanger 102 during heating, and is in parallel relationship with the main throttle device 104.

Next, the effect will be explained. The direction of refrigerant flow during cooling is indicated by solid arrows. First, in the case of normal load during cooling, the high temperature and high pressure refrigerant gas discharged from the compressor 100 is condensed and liquefied in the non-use side heat exchanger 102, and this liquefied refrigerant is passed through the first non-return check. The main throttle part 31 of the main throttle device 104, the electric expansion valve 34, and the third check valve 1 are arranged in parallel through the valve 105 and the dryer 110.
07 and cooling auxiliary capillary reach tube 109
The pressure is reduced in the heat exchanger 103 on the user side, and the gas is evaporated in the heat exchanger 103 on the user side, and returns to the compressor 100 through the four-way valve 101. The operation of the main throttle device 104 and the cooling auxiliary capillary reach tube 109 in this case will be explained based on FIG. 5. Figure 5 is a diagram showing the relationship between the optimum refrigerant circulation amount and the refrigeration load, and shows the optimum refrigerant circulation amount (C-C') at point C, where the load is the smallest during cooling operation.
Capillary reach tube 10 for cooling so that the air flows
9 is selected, and in this case, the electric expansion valve 38
is fully closed, and the solenoid valve 39 is closed. As the refrigeration load gradually increases, the optimum amount of refrigerant circulation also increases, so the electric expansion valve 38 gradually opens to a greater extent as the refrigeration load increases. The opening degree of the electric expansion valve 38 in this case is determined by the outlet water temperature of the user-side heat exchanger 103 and the outside air temperature. Then, at the point where the opening degree of the electric expansion valve 38 is maximum, that is, point A in the figure, the electric expansion valve 38
8 is fully closed, and the solenoid valve 39 is opened. Therefore, at this point, since the refrigerant is controlled by the cooling auxiliary capillary reach tube 109 and the main throttle section 32 of the main throttle device 104, the capillary reach tube of the main throttle section 32 has a refrigerant circulation amount of A-A''. Furthermore, as the refrigeration load increases, the opening degree of the electric expansion valve 38 gradually opens from being fully closed, so that the liquid refrigerant reduced in pressure by the electric expansion valve 38 becomes a refrigerant. It passes through the flow path 33 and exchanges heat with the refrigerant in the main throttle section 32 and evaporates.Also, since the refrigerant in the main throttle section 32 is cooled, the refrigerant in the main throttle section 3
The refrigerant flow rate in 2 increases. That is, the gas content in the two-phase flow of refrigerant generated within the main constriction section 32 decreases as the amount of cooling increases, and the fluid resistance decreases. Therefore, as the opening degree of the electric expansion valve 38 is increased, the amount of cooling is further increased. In this way, it is possible to control up to the maximum optimum refrigerant circulation amount (D-D') for the maximum load (D'), exceeding the maximum optimum refrigerant circulation amount (point B) of the conventional system.

Next, the heating operation will be explained. That is, the refrigerant flow direction is as shown by the broken line arrow, and the high-temperature, high-pressure refrigerant gas discharged from the compressor 100 is condensed and liquefied in the user-side heat exchanger 103, and then passed through the second check valve 106 and the dryer 110. through,
The main throttle part 32, the electric expansion valve 38, and the fourth check valve 108 of the main throttle device 104, which are respectively arranged in parallel.
The pressure is reduced in the heating auxiliary capillary reach tube 111 and evaporated in the non-use side heat exchanger 102.
It passes through the four-way valve 101 and returns to the compressor 100. In this case, the operation of the main throttling device 104 and the heating auxiliary capillary reach tube 111 is the same as in the cooling operation, so that as the heating load increases, the heating auxiliary capillary reach tube 11
1 is selected, the electric expansion valve 38 determines the valve opening degree, and the opening/closing function of the electromagnetic valve 39 is added.

That is, in FIG. 5, in the range C'-A' where the refrigeration load is relatively small, the area covered by ACA'' is the area where the refrigerant circulation amount is secured by the electric expansion valve 38, The section ′ enclosed by CC′A′ is a range in which the amount of refrigerant circulation is ensured by the auxiliary capillary reach tubes 109 and 111. In addition, in the range A'-D' where the refrigeration load is large, the part packed with DAD secures the refrigerant circulation amount with the electric expansion valve 38, and the part packed with DAA''D'' secures the refrigerant circulation with the main constriction part 32.
to secure the refrigerant circulation amount, and the section packed with D″A″A′D′ is the auxiliary capillary reach tube 109, 11.
1 is the range in which the amount of refrigerant circulation is ensured.

Next, the defrost operation will be explained. In this case, the refrigerant flow is the same as during cooling operation (the flow direction is indicated by a solid arrow), but the optimum refrigerant circulation amount cannot be ensured, especially during defrost operation, because the difference between high and low pressures is small. Therefore, after the defrost signal is detected, the electric expansion valve 38 is fully opened and the electromagnetic valve 39 is operated in an open state to shorten the defrost time.

〔Effect of the invention〕

With the above configuration, the optimum refrigerant circulation amount can be ensured over the entire range from operating conditions with low refrigeration load to conditions with large refrigeration load by opening and closing the solenoid valve and adjusting the opening degree of the electric expansion valve. This allows for relatively simple control and optimal control over a wide operating range. Therefore, it is possible to improve the performance and reliability of the air conditioner.

Furthermore, it is also possible to improve the defrost characteristics by fully opening the electric expansion valve and opening the solenoid valve during defrosting.

[Brief explanation of drawings]

Figure 1 is a refrigerant cycle diagram showing a conventional example;
Figure 3 is a configuration diagram showing the configuration of a pressure reducing device, Figure 3 is a diagram showing the relationship between refrigeration load and optimal refrigerant circulation amount, which shows a conventional example, Figure 4 is a refrigeration cycle diagram showing an embodiment of the present invention, and Figure 5 The figure is a diagram showing the relationship between the refrigeration load and the optimum refrigerant circulation amount, showing one embodiment of the present invention. In the figure, 3 is the main throttle part, 38 is an electric expansion valve, 3
9 is a solenoid valve, 100 is a compressor, 101 is a four-way valve,
102 is a non-use side heat exchanger, 103 is a use side heat exchanger, 104 is a main expansion device, 105, 106, 1
07, 108 are first, second, third, and fourth check valves; 109 is an auxiliary capillary reach tube for cooling;
111 is an auxiliary capillary reach tube for heating. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1 A solenoid valve, a main throttling section that reduces the pressure of the liquid refrigerant flowing from the non-use side or the use side heat exchanger that flows through the solenoid valve, and a main throttling section that is provided in parallel with the above-mentioned solenoid valve and the main throttling device, A portion of the refrigerant from the side heat exchanger cools the main throttle section, and the refrigerant flow rate in the bypass channel is determined by the operation state of the bypass passage and the heat pump, which are arranged so as to join with the refrigerant flowing through the main throttle part. A refrigerant flow control device is provided at the inlet and outlet sides of the refrigerant flow control device, and during cooling, the refrigerant from the unused side heat exchanger is First and second check valves that allow the refrigerant to flow to the user-side heat exchanger via the refrigerant flow rate control device, are provided on the inlet side and the outlet side of the refrigerant flow rate control device, and are installed in the user-side heat exchanger during heating. third and fourth check valves that allow the refrigerant from to flow through the refrigerant flow rate control device to the non-use side heat exchanger, an inlet side of the solenoid valve and an outlet side of the second check valve. A cooling auxiliary throttle part that communicates with the inlet side of the solenoid valve and an outlet side of the fourth check valve, and a heating auxiliary throttle part that communicates with the inlet side of the solenoid valve and the outlet side of the fourth check valve, and a refrigerant flow direction of the heat pump cycle that is reversed during the cooling/heating and defrosting operations. The solenoid valve is closed when the load on the heat exchanger on the use side is small during cooling and heating, and the solenoid valve is opened when the heat exchanger on the non-use side is defrosted. A heat pump type air-conditioning device characterized by: